Field of the Invention
The invention relates to a method for rewinding a spinning cake from a spinning pot of a pot spinning apparatus onto a rewinding body, preferably a tube as a yarn carrier, wherein a sliver to be spun is drawn in a drafting configuration, guided by a pneumatic piecing aid, and deposited by a traversing yarn guide in the rotating spinning pot onto an inner wall surface of the spinning pot as a spinning cake and in the process is kept at the requisite rotation for yarn formation.
In pot spinning apparatuses, a sliver that rotates to form the yarn travels on a long path through a yarn guide. The length of the yarn guide must be such that in any intended piecing position in the spinning pot, it can readily be supplied with sliver from the drafting configuration. In order to facilitate the piecing operation, a pneumatic piecing aid is provided, which pneumatically introduces the sliver into the yarn guide tube in the piecing operation. Such an apparatus is known from German Published, Non-Prosecuted Application DE 42 06 030 A1.
Once the spinning operation is ended, which happens when the spinning cake in the spinning pot has reached a predetermined size and needs to be rewound onto a rewinding body, the delivery of sliver from the drafting configuration must be stopped. In pot spinning apparatuses with pneumatic piecing aids, all of the drafting rollers of the drafting configuration, except for the delivery rollers, are therefore stopped. In that process, the sliver is torn between the drafting rollers and the delivery rollers, and the torn end is fed into the yarn guide. As a rule, by the time the sliver tears, the yarn has already been transferred to the tube onto which the spinning cake is to be rewound. The yarn already tears at the tip of the yarn guide upon transfer of the yarn to the tube by the yarn guide. Should that not happen, then a yarn remnant that would hinder the piecing process would remain in the tube of the yarn guide and could not be removed by suction when the sliver is removed by suction at the outlet of the drafting configuration.
Another problem can be the end of the yarn of the spinning cake. Transferring the yarn to the rewinding body is conventionally carried out whenever the yarn guide is pulled out of the spinning pot and the rewinding body has been introduced all the way into the spinning pot. Since the yarn end of the spinning cake is not fixed to the rewinding body during the transfer, the danger exists of the first windings of the package on the rewinding body becoming loose.